Elevator system

ABSTRACT

An elevator system having a car and counterweight interconnected by hoisting and compensating roping. A drive associated with the hoisting roping moves the car and counterweight in guided paths relative to floors of a building, while a compensator sheave tensions and guides the compensating roping. The compensator sheave includes braking apparatus which allows the compensator sheave to freely move with the compensating roping between predetermined vertical limits, automatically adjust for permanent stretch of the hoisting roping while maintaining the predetermined vertical limits of free movement, and to limit upward movement beyond a predetermined limit. The braking apparatus includes brake shoe members carried by the compensator sheave, and fixed guide rail members, with the brake shoe members being biased to grip the guide rail members with a parallelogram squeezing action.

United States Patent [1 1 Solymos 1 1 Sept. 17, 1974 [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Apr. 2, 1973 [21] Appl. No.: 347,285

[75] Inventor:

[52] US. Cl. 187/22, 187/90 [51] Int. Cl B66b 11/00 [58] Field of Search 187/22, 38, 39, 89, 90, 187/91; 188/188, 65.4

[5 6] References Cited UNITED STATES PATENTS 2,295,381 9/1942 Bouton 187/22 2,326,046 8/1943 McCormick" 187/91 X 3,601,227 8/1971 Burch r 187/89 X 3,653,467 4/1972 Showalter 187/22 3,669,223 6/1972 Arnold 188/188 FOREIGN PATENTS OR APPLICATIONS 1,295,150 5/1969 Germany 187/38 Primary ExaminerEvon C. Blunk Assistant Examiner-James L. Rowland Attorney, Agent, or FirmD. R. Lackey; Clement L. McHale [57] ABSTRACT An elevator system having a car and counterweight interconnected by hoisting and compensating roping. A drive associated with the hoisting roping moves the car and counterweight in guided paths relative to floors of a building, while a compensator sheave tensions and guides the compensating roping. The compensator sheave includes braking apparatus which allows the compensator sheave to freely move with the compensating roping between predetermined vertical limits, automatically adjust for permanent stretch of the hoisting roping while maintaining the predetermined vertical limits of free movement, and to limit upward movement beyond a predetermined limit. The braking apparatus includes brake shoe members carried by the compensator sheave, and fixed guide rail members, with the brake shoe members being biased to grip the guide rail members with a parallelogram squeezing action.

13 Claims, 11 Drawing Figures PAIENTEDSEPWW 3,835,959

sum 3 or 3 v F|G.6 FIG? FIGJO FIG. n

ELEVATOR SYSTEM BACKGROUND or THE INVENTION 1. Field of the Invention The invention relates in general to elevator systems, and more specifically to elevator systems which use compensating roping and compensator sheaves.

2. Description of the Prior Art It is conventional in elevator systems which travel at a rate of about 500 feet per minute, and above, to provide rope compensation in order to more closely balance the car and counterweight at all positions thereof. The compensating roping is fastened to the bottom of the car, it runs downwardly towards and about a weighted compensator sheave in the pit, and then it extends upwardly to the counterweight, where it is also fastened.

It is also conventional to tie or lock-down the compensator sheave. The lock-down apparatus employed usually allows a small vertical float of the compensator sheave, to accommodate temporary or elastic variations in the length of the hoisting roping, such as due to loading, temperature, and acceleration of the loads. Upward movement above the upper limit of the float locks the compensator sheave to its guides, and downward movement below the lower limit of the float, such as due to permanent stretch of the hoist roping, lowers the point of locking of the compensator sheave arrangement to its guides. The lock-down of the compensator sheave ties the counterweight to the car such that both will decelerate at substantially the same rate'during rapid deceleration of either the car or the counterweight. For example, when the car decelerates rapidly, such as due to a safety or a buffer stop, or the counterweight decelerates rapidly, such as due to a buffer stop, the counterweight, or car, respectively, will not continue to rise at a rate which allows substantial slackening of the hoisting ropes. This prevents the sudden jerking of the hoisting ropes which would otherwise occur if the car and counterweight were not tied together during the rapid deceleration of either the car or the counterweight.

Various lock-down compensator arrangements have been used in the prior art. For example, US. Pat. No. 1,789,008 teaches two different approaches, a rack and pawl arrangement, and a wedge arrangement. US. Pat. Nos. 1,976,494 and 2,295,381 both disclose the use of inclined planes which cooperate with levers to squeeze jaws tightly against the compensator guide rails when the compensator sheave rises. US. Pat. Nos. 1,905,273 and 2,270,441 disclose roping arrangements for tying down the compensator sheave. US. Pat. No. 1,953,l l9 teaches a wedge arrangement. US. Pat. No. 1,944,772 teaches a motor operated bias arrangement. US. Pat. No. 1,861,063 illustrates a compensator sheave having a piston-cylinder-valve arrangement for allowing slow up and down movement of the compensator arrangement, but preventing a rapid change in position.

While all of these approaches are successful in tying the car and the counterweight together during a rapid deceleration of one of the objects, some of these arrangements are very complex and therefore costly to manufacture, and some, especially those which utilize a wedge arrangement, lock the locking arrangement so tightly to its guides when it is called upon to limit the upward travel of the compensator sheave, that the locking arrangement will not self-release, making it necessary for maintenance personnel to release the locking grip.

SUMMARY OF THE INVENTION Briefly, the present invention is a new and improved elevator system having a car and counterweight interconnected by hoisting and compensating roping, and including a compensator which includes a new and improved lock-down arrangement. The new and improved lock-down arrangement is simple in construction, self-releasing after a safety or buffer stop when it is necessary to adjust the locking position on the guide rails, and it incorporates the functions of allowing the compensator sheave to float vertically within predetermined limits due to normal elastic stretch of the hoisting roping, and tov move the locking point downwardly to accommodate permanent stretch of the hoisting roping while maintaining predetermined float limits at each new locking location.

The lock-down compensator arrangement includes braking apparatus having gripping or brake shoe members which are disposed to grip the guide rails of the compensator with a parallelogram squeezing action, which, along with cooperative biasing means, permits predetermined vertical movement of the compensator. Downward movement of the compensator sheave to the lower limit overcomes a bias which ordinarily locks the locking arrangement to release the gripping action of the parallelogram arrangement and move the locking point further down the guide rails. This will automatically occur to accommodate permanent stretch of the hoisting roping. Movement of the compensator sheave in an upward direction is allowed until the bias membes, i.e., a spring, pipes against the braking apparatus, and further upward movement of the compensator sheave is then prevented to tie the car and counterweight together for achieving similar deceleration rates during a safety or buffer stop.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be better-understood, and further advantages and uses thereof more readily apparent, when considered in view of the following detailed description of exemplary embodiments, taken with the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of an elevator system having a compensator which may be constructed according to the teachings of the invention;

FIG. 2 is an elevational view, partially in section, of a compensator and lock-down arrangement constructed according to the teachings of the invention;

FIG. 3 is an end elevational view of the compensator and lock-down arrangement shown in FIG. 2;

FIG. 4 is a plan view of the compensator and lockdown arrangement shown in FIG. 2;

FIG. 5 is a perspective view of the locking device of the compensator and lock-down arrangement shown in FIGS. 2, 3 and 4;

FIGS. 6 and 7 are front and side elevational views, respectively, of the brake shoe used in the locking arrangement shown in FIG. 5;

FIGS. 8 and 9 are front and plan views, respectively, of the brake lever assembly which pivotally interconnects the brake shoes; and

FIGS. and 11 are plan views of the top and bottom plate members which are used to secure one of the brake shoe members of the locking arrangement.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, and FIG. 1 in particular, there is shown an elevator system 10 which may be constructed according to the teachings of the invention. The elevator system 10 includes an elevator car 12 mounted for movement in a hoistway 14 of a building 15 having a plurality of floors which are indicated generally at 16, which floors are served by the elevator car 12. An elevator drive motor 18, which may be disposed in the penthouse 21 of the building 15, drives a traction sheave 19 via a drive shaft 20, and, if required, an idler or deflection sheave 22 may be used in combination with the traction sheave, and disposed, for example on the lower surface of the penthouse floor.

Hoisting ropes or cables 24 interconnect the elevator car 12 with a counterweight 26, with the hoisting ropes 24 extending from the car 12, about the traction and idler sheaves l9 and 22, respectively, using the full wrap illustrated, or a half wrap, as desired, and then to the counterweight 26. The hoisting ropes 24 may be connected to the overhead channels of the elevator car and counterwight, if the roping is l to l, as illustrated, or the hoisting roping may be disposed about sheaves carried by the car and/or counterweight, ir either is roped 2 to l, in which event the ends of the hoisting ropes would be dead ended above the travel paths of the car and/or counterweight.

Compensating roping 28 interconnects the elevator car 12 with the counterweight 26. The compensating roping 28 is associated with a compensator arrangement 29 disposed below the path of travel of the elevator car and counterweight, such as in the pit 32, with the roping 28 being reeved about a compensator sheave 30 such that the sheave 30 hangs in the loop of the compensator roping. The compensator sheave 30 is rotatably mounted on a frame 34, and the frame 34 and compensator sheave 30 are mounted for constrained vertical movement via guide rails 36 and 38, which may be similar to the T-shaped guide rails used to guide the car and counterweight.

The compensator sheave 30 must be allowed limited vertical movement to accommodate temporary changes in the length of the hoisting roping 24. However, upward movement of the compensator sheave 30 beyond the upper vertical limit allowed for temporary changes in the length of the hoisting rope must be prevented. Further, the compensator sheave arrangement must be such that it will accommodate permanent stretch of the hoisting ropes without loss of ability to accommodate elastic or temporary changes in the length of the hoisting rope.

FIGS. 2, 3 and 4 illustrate front, side and plan views, respectively, of a new and improved compensator arrangement 29 which may be used with the elevator system shown in FIG. 1 and which will provide the required functions of a tied down compensator sheave with a rugged, uncomplicated structure which will not lock after a buffer or safety stop such that normal automatic readjustment of the locking location on the guides is prevented.

More specifically, compensator arrangement 29 includes a frame 34 which includes a box-like structure formed of four spaced vertically oriented channel members 40, 42, 44 and 46, a top member 48 which joins the upper ends of the channel members, and a bottom member 50 which joins their lower ends. Channel members 40 and 42 are disposed to provide a first pair of channels, being held in spaced relation at one end of the frame 34 such that their back or bight portions are parallel and spaced a predetermined distance apart. More specifically, channel member 40 includes a main or bight portion 41 and first and second flange members 43 and 45 which extend perpendicularly outward from one side of the bight 41. Channel member 42 includes a main or bight portion 47 and first and second flange members 49 and 51 which extend perpendicularly outward from one side of bight 47. The sides of the bights 41 and 47 opposite to their flanged sides are disposed to face one another, as best illustrated in FIG. 4.

In like manner, channel members 44 and 46 form a second pair at the other end of the'frame 34.

A shaft member is secured to the first and second pairs of channel members, such as by machining parallel flat portions on each end of the shaft member such that the flat portions will snugly extend between the channel members of each pair at substantially the midpoints of the longitudinal dimensions of the channel members. The flat portions of the shaft member 52 may be drilled and tapped and these openings aligned with openings in the channel members for receiving bolts which will secure the shaft member to the frame 34. The longitudinal axis 54 of the shaft member is horizontal, or parallel to the major surfaces of the top and bottom members 48 and 50, respectively.

Before the shaft member 52 is secured to the frame 34, however, sheave 30 is journaled for rotation on the shaft member 52, such as by bearings 56. Two grooves 58 and 60 are shown for accommodating two compensating ropes 28 and 28', but it may have a single groove, in which event it-would be disposed on the center line 62 shown in FIG. 2, or more than two grooves may be used, if required.

The lock-down arrangement for sheave 30 and its support frame 34 includes first and second braking or locking arrangements 64 and 66, associated with the first and second pairs of channel members, respectively. Since the braking or locking arrangements 64 and 66 are of like construction, only arrangement 64 will be described in detail. In describing braking arrangement 64, FIG. 5, which is a perspective view of locking arrangement 64, and FIGS. 6l1, which illustrate details of the locking arrangement 64, will be referred to in addition to FIGS. 2, 3 and 4 which illustrate the braking arrangement in position with its compensator sheave arrangement.

Braking arrangement 64 includes a brake assembly 70 comprising first and second brake shoe members 72 and 74 and an interconnecting brake lever assembly 76. Brake shoe member 74 is welded to structural frame assembly 78, which includes spaced parallel top and bottom members and 82, respectively, a back member 84 which interconnects the top and bottom members 80 and 82, and a tubular depending member 86. The top member 80 includes front and back portions 88 and 90, respectively, side portions 92 and 93, and first and second flat major opposed surfaces 94 and 96, respectively. The front portion 88 has a slot 98 formed therein which starts at the front 88 and extends toward the back for a predetermined dimension, terminating in a portion 99 with the width and depth of the slot 98 being selected to freely accept the projecting portion 100 of guide rail 38 without binding. The slot 98 divides the first portion into first and projecting portions 102 and 104, respectively. The bottom member 82 is similar to the top member 80, with like reference numerals except for a prime mark indicating like portions of the members. FIGS. and 11 are plan views of the top and bottom members 80 and 82, respectively. The top and bottom members 80 and 82 are similar in construction except the outwardly extending portion 102 of the top portion 80 is eliminated in the bottom portion 82, such that the bottom portion 82 has a single projecting portion 104' at the front portion 88.

The back plate member 84 is secured to the top and bottom plate members 80 and 82, such as by welding, and brake shoe member 74 is disposed snugly between the parallel facing major surfaces of the projecting portions 104 and 104' of the top and bottom member 80 and 82, and secured thereto, such as by welding.

The top and bottom members 80 and 82 each define a circular opening 110 and 110, respectively, which openings extend between their major opposed surfaces. The cylindrical or tubular depending portion 86 is secured to the major surface 96' of the bottom member, with the opening in the depending member disposed to surround the opening 110 in the bottom member 82. A plurality of stiffening members, such as stiffening members 111 shown in FIGS. 2 and 3, may be welded to the top and back members, and the bottom and back members. The stiffening members are omitted from the perspective view of FIG. 5 for clarity.

Each of the brake shoe members 72 and 74 are of similar construction, being formed of a suitable metal, such as steel, and it is thus only necessary to describe member 72 in detail. Member 72 includes first and second end portions 120 and 122, front and back portions 124 and 126, and first and second side portions 128 and 130, respectively. An opening 132 extends between the front and back portions, with the center line 134 of the opening being in approximately the geometrical center of the front portion. Opening 132 is preferably non-round, with the most desirable configuration being suqare, or round cornered square, as illustrated, for purposes which will be hereinafter explained.

The brake shoe members 72 and 74 are pivotally interconnected by brake lever assembly 76. Brake lever assembly 76 includes a back or lever portion 140 and first and second cylindrical pin members 142 and 144 which extend perpendicularly outward from a common side of lever 140. Lever 140, for example, may be constructed with two spaced openings therein which extend between its major opposed surfaces, with the openings being sized to receive the pin members 142 and 144 with a press fit. The ends of the pins which are adjacent to the lever may then be welded to the lever, as indicated in FIG. 9. Openings 146 and 148 are disposed through pin members 142 and 144, respectively, with the openings being perpendicular to the longitudinal center lines of the pin members, and with the openings being located adjacent to their outwardly extending ends.

As best illustrated in FIG. 5, the pin member 144 of the brake lever assembly 76 is disposed through the opening 132 of brake shoe member 74. A washer member 150 is disposed about the end of pin member 144 which extends past the front surface of the brake shoe member, and a roll pin 152 is disposed through opening 148 to pivotally secure the brake lever assembly 76 to the brake shoe member 74. In like manner, pin 142 is disposed through the opening in brake shoe member 72 and secured thereto by washer member 154 and roll pin 156. The spacing between the longitudinal center lines of pin members 142 and 144 is selected such that the facing surfaces of the brake shoe member will separate by a distance sufficient to receive the projecting portion of the guide rail 38 when the brake shoe 72 is pivoted upwardly such that its upper surface is substantially in the same plane as the corresponding surface on brake shoe member 74. It will be noted that projection 102 on the top member 80 prevents the brake shoe member 72 from pivoting upwardly past the vertical location of the brake shoe member 74.

As illustrated in FIGS. 2, 3 and 5, a plate member having a tubular projection 162 disposed on its upper surface 164 is fixed between the channel members 40 and 42 of the first pair of channel members, adjacent to the upper surface of shaft member 52. The plate member 160 may be fixed to the channel members, such as by providing tapped openings 166 in opposite edges of the plate member 160, which openings are aligned with openings through the channel members and secured in position by bolts. Plate member 160 forms a spring plate and projection 162 a lower spring seat for a compression spring member 170. The brake assembly 70 is disposed between channel members 42 and 44 such that the opening in the depending .projection 86 is aligned vertically with the opening in the lower spring seat 162. Depending portion 86 receives the upper end of the compression spring or bias member 170, and thus provides the upper spring seat. A tubular member or guide rod 174 is disposed through the aligned openings in the top and bottom members 80 and 82, respectively, of the brake assembly 64 through the opening in the upper spring seat 86, through the opening in the spring 170, through the opening in the lower spring seat 162, and into a snugly sized opening in the spring plate 160. The upper end of the guide rod 174 is secured to a plate member 176 which also serves to define one of the vertical limits between which the compensator sheave 30 may move at any one locking location of the locking or braking arrangement 64 on the guide rail 38. The braking or locking assembly 64 is guided in a vertical path between the first pair of channel members by the guide rod 174.

In the operation of the braking arrangement 64, the sheave 30 rests in the loop of the compensator roping and field personnel initially set the working spring length 180 to a predetermined dimension by pushing the assembly 64 downwardly from the top portion of member 80. This releases the locking grip of the locking arrangement 64 and enables it to be pushed down wardly against the bias of the compression spring 170. When the predetermined dimension 180 is reached, the downward force on the top member 80 is released and the upward spring bias is applied entirely to the brake shoe member 74 via the box-like construction to which the brake shoe member '74 is secured. This upward force on the brake shoe member 74 causes brake lever 76 to pivot about the center line of pin 144, pushing the brake shoe member 72 downwardly to squeeze or pinch the projecting portion 100 of the guide rail 38 between the brake shoe members. This parallelogram mechanical action of the brake shoe members 72 and 74 locks the assembly 64 to the guide rail 38 with an action which increases its gripping force as the spring force on the bottom plate member 82 increases.

When the dimensions of the hoisting roping temporarily change due to loading, temperature, acceleration of the loads, and the like, the sheave 30 and frame 34 move freely up and down between predetermined limits. For example, assume that the length dimension of the hoisting ropes increases. The sheave 30 and frame 34 will move vertically downward. Since the position of the locking arrangement 64 on the guide rail 38 does not change, the working dimension of the spring increases, but the spring still maintains a locking bias on the locking arrangement 64. The limit to which the sheave 30 and frame 34 may descend at any one locking location of locking assembly 64 on the guide rail 38 is the distance 182 between the top surface of member 80 and the bottom surface of member 176. This distance will usually not be reached due to temporary or elastic changes in the length of the hoisting roping. However, when the hoisting ropes permanently stretch, the permanent stretch plus elastic changes in the hoistingroping will cause the limit to be reached, with the bottom surface of member 176 striking the top of member 80. When this occurs, the upward bias of the spring member 170 is overcome by the downward force provided by the weight of the frame and compensator sheave assembly, causing the locking arrangement 64 to release its grip on the guide rail and move downwardly on the guide rail 38 as far as it is pushed. Thus, the locking arrangement 64, as well as its companion locking arrangement 66 will automatically be moved downwardly to a new lower locking position on the guide rails 38 and 36, respectively, to accommodate permanent lengthening of the hoisting roping. When this occurs, the compensator sheave and frame are still free to move upwardly and downwardly between upper and lower limits, due to temporary changes in the length of the hoisting roping. If the permanent stretch in the length of the hoisting roping reaches a predetermined dimension, a limit switch 188 fastened to the frame 34 is actuated by an operating arm 190 carried by the locking arrangement 64 to initiate a predetermined control action, such as parking the elevator car at the closest landing with its doors open, and taking the car out of service.

The upper limit to which the sheave 30 and frame 34 may rise is determined by the amount the spring member 170 will compress until it pipes. Once the spring 170 pipes, which will occur in the event of a buffer stop by the car or counterweight, or a safety stop by the car, the sheave and frame are locked to the guide rails 38 and 36 by the locking arrangements 64 and 66, respectively, and thus the car and counterweight will be tied together and will decelerate at the same rate.

The locking arrangement 64 will not permanently lock to the guide rail 38 after a safety or buffer stop, due to the parallelogram locking arrangement. The round cross-sectional configuration of the pin members 142 and 144 and the non-round configuration of the cooperative openings 132 in the brake shoe members insure that there will be no wedging action between them, precluding a binding or a wedging which might otherwise cause an unreleasing grip. Simply overcoming the upward bias of the spring member 170 by pressing downwardly on the top member 80, such as by the action of member 176 contacting and pressing the top member downwardly, will pivot brake shoe 72 upwardly and release the grip of the parallelogram locking action. Therefore, maintenance personnel are not required to go into the pit to unbind the locking mechanism after a buffer or safety stop.

In summary, there has been disclosed a new and improved elevator system having a compensator arrangement which is rugged, uncomplicated, and therefore not as costly to manufacture as certain of the prior art arrangements. Further, the structure of the locking arrangement for the compensator is such that it precludes binding or jamming of the locking arrangement after a safety or buffer stop. Thus, it will not require the attention of maintenance personnel after a buffer or safety stop, as it automatically will perform its required functions as they are required.

I claim as my invention:

1. An elevator system, comprising:

an elevator car,

a counterweight,

motive means for said car and counterweight including hoisting roping interconnecting the car and counterweight,

compensating roping interconnecting the car and counterweight,

a compensator sheave for tensioning and guiding said compensating roping,

and means for limiting the upward movement of said compensator sheave including fixed, vertically extending, guide rail means, and gripping means carried by the compensator sheave for gripping said guide rail means, said gripping means including first and second members disposed in spaced relation on opposite sides of a predetermined portion of said guide rail means, linking means, means pivotally connecting each of said first and second members to said linking means such that upward movement of said first member pivots said linking means and said second member downwardly to reduce the spacing between the first and second members and cause said first and second members to grip the guide rail means, and biasing means urging said first member in an upward direction.

2. The elevator system of claim 1 wherein the guide rail means includes first and second guide rails and the gripping means includes first and second sets of cooperatively associated first and second members for gripping said first and second guide rails, respectively.

3. The elevator system of claim 1 including a frame, means rotatably supporting the compensator sheave on said frame, and wherein the gripping means and biasing means are carried by said frame, same frame and compensator sheave being adjustably locked to the guide rail means by the gripping means through the biasing means.

4. The elevator system of claim 1 including means carried by the compensator sheave which overcomes the bias against the first member applied thereto by the biasing means when the hoisting roping stretches to a point which necessitates movement of the gripping means to a new location on the guide rail means.

5. The elevator system of claim 1 wherein the biasing means includes a spring member disposed below the position of the first member to bias the first member in an upward direction, and including adjusting means carried by the compensator sheave spaced vertically above the first member such that a predetermined downward movement of the compensator sheave will cause the adjusting means to overcome the bias on the first member of the gripping means to release the grip of the gripping means and move the first and second members of the gripping means to a new lower gripping position on the guide rail means, with the spring member and adjusting means allowing predetermined up and down movement of the compensator sheave while preventing upward movement of the compensator sheave when upward movement thereof reaches a point which completely compresses said spring member.

6. The elevator system of claim 1 wherein the first and second members are first and second brake shoes, respectively, each of which define an opening therein, and the linking means for pivotally interconnecting the first and second members includes a lever portion having spaced parallel first and second members extending outwardly therefrom which enter the openings in the first and second brake shoes, respectively.

7. The elevator system of claim 6 wherein the first and second spaced parallel members of the lever each have a substantiallycircular cross-sectional configuration, and the openings in the first and second brake shoes for receiving the first and second spaced parallel members have a non-round cross-sectional configuration.

8. The elevator system of claim 7 wherein the openings defined by the first and second brake shoes have a substantially square cross-sectional configuration.

9. The elevator system of claim 1 including a support frame, means rotatably mounting the compensator sheave in said support frame, and wherein the biasing means is a spring member which extends between a portion of said support frame and the first member, with the spring member permitting upward movement of the support frame and compensator sheave until the spring member is completely compressed.

10. The elevator system of claim 9 including means compensating for permanent stretch of the hoisting roping by moving the gripping location of the gripping means lower on the guide rail means, including means associated with the support frame for overcoming the upward bias on the first member to release the grip of the gripping means on the guide rail means and move the gripping location to a lower position thereon.

11. The elevator system of claim 1 including a support frame, means rotatably mounting the compensator sheave in said support frame, and vertically oriented guide means carried by said support frame, and wherein the bias means is a spring member, the first member of the gripping means is slidably mounted on said vertically oriented guide means, and the spring member is mounted on said vertically oriented guide means, between said first member of the gripping means and a portion of said support frame.

12. The elevator system of claim 1 wherein the biasing means includes a single spring member for biasing the cooperatively associated assembly of first and second members, with the upward biasing of the first member being transferred to the second member through the linking means to bias it downwardly.

l3. The-elevator system of claim 1 wherein the first and second members of the gripping means are elongated first and second brake shoe members, respectively, having their longitudinal axes substantially vertically oriented, and the linking means includes a single lever portion cooperatively associated with the first and second brake shoe members, with the pivot axes of the means which pivotally connects the first and second members to the single lever portion being located at substantially the midpoint of the longitudinal axes of the first and second brake shoe members. 

1. An elevator system, comprising: an elevator car, a counterweight, motive means for said car and counterweight including hoisting roping interconnecting the car and counterweight, compensating roping interconnecting the car and counterweight, a compensator sheave for tensioning and guiding said compensating roping, and means for limiting the upward movement of said compensator sheave including fixed, vertically extending, guide rail means, and gripping means carried by the compensator sheave for gripping said guide rail means, said gripping means including first and second members disposed in spaced relation on opposite sides of a predetermined portion of said guide rail means, linking means, means pivotally connecting each of said first and second members to said linking means such that upward movement of said first member pivots said linking means and said second member downwardly to reduce the spacing between the first and second members and cause said first and second members to grip the guide rail means, and biasing means urging said first member in an upward direction.
 2. The elevator system of claim 1 wherein the guide rail means includes first and second guide rails and the gripping means includes first and second sets of cooperatively associated first and second members for gripping said first and second guide rails, respectively.
 3. The elevator system of claim 1 including a frame, means rotatably supporting the compensator sheave on said frame, and wherein the gripping means and biasing means are carried by said frame, same frame and compensator sheave being adjustably locked to the guide rail means by the gripping means through the biasing means.
 4. The elevator system of claim 1 including means carried by the compensator sheave which Overcomes the bias against the first member applied thereto by the biasing means when the hoisting roping stretches to a point which necessitates movement of the gripping means to a new location on the guide rail means.
 5. The elevator system of claim 1 wherein the biasing means includes a spring member disposed below the position of the first member to bias the first member in an upward direction, and including adjusting means carried by the compensator sheave spaced vertically above the first member such that a predetermined downward movement of the compensator sheave will cause the adjusting means to overcome the bias on the first member of the gripping means to release the grip of the gripping means and move the first and second members of the gripping means to a new lower gripping position on the guide rail means, with the spring member and adjusting means allowing predetermined up and down movement of the compensator sheave while preventing upward movement of the compensator sheave when upward movement thereof reaches a point which completely compresses said spring member.
 6. The elevator system of claim 1 wherein the first and second members are first and second brake shoes, respectively, each of which define an opening therein, and the linking means for pivotally interconnecting the first and second members includes a lever portion having spaced parallel first and second members extending outwardly therefrom which enter the openings in the first and second brake shoes, respectively.
 7. The elevator system of claim 6 wherein the first and second spaced parallel members of the lever each have a substantially circular cross-sectional configuration, and the openings in the first and second brake shoes for receiving the first and second spaced parallel members have a non-round cross-sectional configuration.
 8. The elevator system of claim 7 wherein the openings defined by the first and second brake shoes have a substantially square cross-sectional configuration.
 9. The elevator system of claim 1 including a support frame, means rotatably mounting the compensator sheave in said support frame, and wherein the biasing means is a spring member which extends between a portion of said support frame and the first member, with the spring member permitting upward movement of the support frame and compensator sheave until the spring member is completely compressed.
 10. The elevator system of claim 9 including means compensating for permanent stretch of the hoisting roping by moving the gripping location of the gripping means lower on the guide rail means, including means associated with the support frame for overcoming the upward bias on the first member to release the grip of the gripping means on the guide rail means and move the gripping location to a lower position thereon.
 11. The elevator system of claim 1 including a support frame, means rotatably mounting the compensator sheave in said support frame, and vertically oriented guide means carried by said support frame, and wherein the bias means is a spring member, the first member of the gripping means is slidably mounted on said vertically oriented guide means, and the spring member is mounted on said vertically oriented guide means, between said first member of the gripping means and a portion of said support frame.
 12. The elevator system of claim 1 wherein the biasing means includes a single spring member for biasing the cooperatively associated assembly of first and second members, with the upward biasing of the first member being transferred to the second member through the linking means to bias it downwardly.
 13. The elevator system of claim 1 wherein the first and second members of the gripping means are elongated first and second brake shoe members, respectively, having their longitudinal axes substantially vertically oriented, and the linking means includes a single lever portion cooperatively associated with the first and second brake shoe members, with the pivot axes of the means which pivotally conneCts the first and second members to the single lever portion being located at substantially the midpoint of the longitudinal axes of the first and second brake shoe members. 